Friction tube construction



7, 1951 c. MERRYMAN FRICTION TUBE CONSTRUCTION Filed Jan. 50, 195].

. IN VEN TOR. fla l fife/r3772 (2 72,

Patented Aug. 7, 1951 UNITEDSTATES PATENT OFFICE 2,563,128 r niorrrou TUBE CONSTRUCTION Carl Merryman, Melrose Park, Ill'., assignor to Dur-O-Lite Pencil Company; Melrose Park, Ill., a corporation of Delaware Application January 30, 1951; Serial No. 208,488

4 3'Qlaims. 1

This invention relates'to a new and improved mechanical pencil and more particularly to a construction of such a pencil whereby the parts are more readily assembled for use.

The invention relates to the type of pencil having a hollow barrel and a removable tip to which is secured a spiral lead guide and feed tube. The inner face of the. barrel is. provided; witha longitudinal groove and a follower or plunger is fitted into the spiral feed tube, with an actuatin portion extending through the spiral opening and into the barrel groove. Thus when the tip and tube are rotated relative to'the barrelthe follower is forced downwardly and feeds lead in the tube out through the tip of the pencil. The barrel is provided with a friction tube which extends from the lower end of the tip. This friction tube is resilient and frictionally grips an inner face of the tip. It thus holds the tip in place while permitting it to be rotated relative to the barrel.

The friction tube is provided with a longitudinal slot in alignment with the longitudinal groove in the barrel so that the follower passesthrough the slot and into the groove when the tip and spiral lead guide are inserted. It has been customary to form the lower face of the friction tube with a transverse edge across the axis of the pencil.

It is an object of the present invention to provide a new and improved mechanical pencil with the parts formed to facilitate assembly.

It is a further object to provide a pencil of this type having a split friction tube with its lower face formed to facilitate entry of a lead follower into the split in the tube.

It is also an object to provide such a pencil with a friction tube having an inclined surface whereby axial pressure in assembling the parts gives a cam action to the follower, forcing it into the split in the friction tube.

It is an additional object to provide a pencil construction which is simple in design and operation and adapted for commercial production and use.

Other and further objects will appear as the description proceeds.

I have shown certain preferred embodiments of my invention in the accompanying drawings in which Figure l is an elevation of a complete pencil;

Figure 2 is a partly broken away view on an enlarged scale showing the internal construction;

Figure 3 is a section taken on line 3-3 of Figure 2;

. 2 Figure 4 is a perspective view of theform of friction tube shown in Figure 2; and

Figure-5 is a partial elevation showing another 'form of friction tube with the parts partially assembled.

In the drawings the pencil is shown as having a hollow barrel H and a removable metal tip l3 from which the lead l 5- extends. The barrel II is provided with an internal longitudinal groove I! to receive, the actuating portion IQ of the follower. 20'. The tip 13 has a conical flange 2| abutting the shoulder 23 on the barrel II. The tip [3 also has an internal cylindrical recess 25 surrounding the spiral lead guide or feed tube 2.1. which has, its lower end permanently secured to the tip.

The resilient friction tube 29 which is formed of spring metal, is secured in the lower end of the barrel II and extends downwardly therefrom. This tube 29 is split as shown at 3| and is of a size to permit free passage of the guide tube 21. The split at 3| is aligned with the groove I! in the inner face of the barrel and is of substantially the same width as the groove. The outer face of the lower portion of the tube 29 resiliently grips the inner face of the cylindrical recess 25 in the tip [3 to hold the tip in place on the barrel while permitting manual rotation of the tip relative to the barrel.

The lower edge of the friction tube 29 is sloped at an angle upwardly toward split 3| in the tube. In the form of construction shown in Figures 2 and 4 the lower end of the tube is cut oil at an angle to form the lower edge 33 with a rounded high point opposite the split 3|. In this form of construction the portion 19 of the follower 23 will be thrust to one side or the other into the split 3! when the parts are assembled. It will be understood that the assembly comprises grasping the barrel II in one hand and the tip l3 in the other and in thrusting the tube 21 carried by the tip l3 up into the barrel ll until the tip flange 2| abuts against the shoulder 23 on the barrel. The cam action of the lower edge 33 of the tube 29 will cause the portion 19 of the follower 20 to have a rotary motion until it enters the split 31, the direction of the motion depending upon which side of the high point of the cam edge 33 the portion I9 first engages.

In the form of construction shown in Figure 5, the lower edge of the tube 39 has a continuous slope from a high side at 35 adjacent one edge of split 4| to a low side at 36 adjacent the opposite edge of the split 4|. Thus if the portion 19 of the follower 2|] does not happen to enter the split 4| directly when the parts are assembled it will be rotated in one direction until it does enter the split.

It is to be noted that the direction of the slope between the high point 35 and low point 36 is such that when the portion I9 of follower 20 is thrust in a. rotary direction by the cam action of the surface, this rotary movement is in the direction to move the follower down in the spiral opening 28 rather than upwardly out of the opening. It will be understood that the parts may be assembled with the portion [9 of follower 20 resting on the upper edge of the spiral tube 21 rather than actually in the feed spiral opening 28. In such case the cam action will rotate the portion 19 until it enters the spiral opening.

While I have shown certain preferred embodiments of my invention, it is capable of variation to meet differing requirements and I contemplate such modifications as come within the spirit and scope of the appended claims.

In the claims:

1. In a mechanical pencil having a hollow barrel with a longitudinal internal groove, 9. lead follower carried by a spiral tube secured to a removable tip, the follower having a portion fitting in the barrel groove when the parts are in assembled relation, a friction tube carried by the barrel with a lower portion frictionally gripping the tip, the tube having a split aligned with the groove in the barrel, the lower edge of the friction tube being formed as a cam surface to guide the follower into the split and groove.

2. In a mechanical pencil having a hollow barrel with a longitudinal internal groove, a lead follower carried by a spiral tube secured to a removable tip, the follower having a portion fltting in the barrel groove when the parts are in assembled relation, a friction tube carried by the barrel with a lower portion frictionall gripping the tip, the tube having a split aligned with the groove in the barrel, the lower edge of the friction tube being formed as a cam surface to guide the follower into the split and'groove, said cam surface having a high point opposite the split and sloping in both directions toward the split.

3. In a mechanical pencil having a hollow barrel with a, longitudinal internal groove, a lead follower carried by a spiral tube secured to a removable tip, the follower having a portion fitting in the barrel groove when the parts are in assembled relation, a friction tube carried by the barrel with a lower portion frictionally gripping the tip, the tube having a split aligned with the groove in the barrel, the lower edge of the friction tube being formed as a cam surface to guide the follower into the split and groove, said cam surface having a high point adjacent one side of the split and sloping toward the other side of the split.

CARL MERRYMAN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,161,889 Schaefi'er June 13, 1939 2,164,166 Schaeffer June 27, 1939 2,356,509 Deli Aug. 22, 1944 

